[Formation of an alimentary motor conditioned reflex to photic stimulation in young rhesus monkeys].

It is possible to form a positive motor alimentary conditioned reflex to red colour and a negative conditioned reflex (differentiation) to green, in the young of rhesus monkeys, four-to six-week old, which testifies to their capacity of differentiating these colour stimuli. The orienting reflex takes an active part in the formation of both reflexes. Elaboration in the four-week old monkeys not only of a positive but also a differentiating motor alimentary conditioned reflex attests that at this age the cerebral cortex is already actively exercising the function of an integrator of inhibitory processes, not only of excitation.